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https://issues.apache.org/jira/browse/ACCUMULO-4112?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15186490#comment-15186490
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ASF GitHub Bot commented on ACCUMULO-4112:
------------------------------------------
Github user wjsl commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/79#discussion_r55471617
--- Diff:
server/tserver/src/main/java/org/apache/accumulo/tserver/TabletServer.java ---
@@ -2966,13 +2966,26 @@ public Void run() {
}
}
+ private Durability getMincEventDurability(KeyExtent extent) {
+ TableConfiguration conf;
+ if (extent.isMeta() || extent.isRootTablet()) {
--- End diff --
This check is a bit confusing. To me it reads "If the extent is for the
metadata table or the root tablet, use the root tablet's configuration.
Otherwise, use the metadata configuration." Is there some other setting for
user tables that's more appropriate?
`KeyExtent#isMeta` already returns whether or not it's for the metadata
table or the root tablet, so the `|| extent.isRootTablet()` is redundant.
However, I think refactoring `KeyExtent#isMeta` is more appropriate to make it
more clear about what it is checking.
> Poor performance due to MinC start/stop updates are always hsync'd
> ------------------------------------------------------------------
>
> Key: ACCUMULO-4112
> URL: https://issues.apache.org/jira/browse/ACCUMULO-4112
> Project: Accumulo
> Issue Type: Bug
> Components: tserver
> Environment: Fluo testing on a 20-node cluster
> Reporter: Eric Newton
> Assignee: Keith Turner
> Priority: Critical
> Fix For: 1.7.2, 1.8.0
>
> Attachments: HSyncOverheadExperiment.png, MinCFlushPerfTest.java,
> Sync-Flush-Log-Performance.png
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> [~kturner] writes:
> {quote}
> I was running a Fluo test with 1.8.0-SNAP on my workstation. My Fluo table
> had a ton of tablets. I was seeing terrible performance. I started
> looking at the tserver and noticed it was always calling hsync. I tracked
> down the problem to the fact that when minc start and stop events are written
> to the log they are always written w/ sync level. My poor little tserver
> was constantly minor compacting (probably had around 600 tablets that were
> all being written to).
> I changed the test config to create like 15 tablets and the performance was
> much better. All cores were 100% utilized, which was not the case when hsync
> was always called.
> {quote}
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